EVIDENCE has been presented that sera of schizophrenic patients may contain a factor, or factors, not present in normal sera which are capable of influencing carbohydrate metabolism of various tissues, eg, chicken erythrocytes,1,2 yeast cells,3 and rat diaphragm.4 Serum effects on chicken erythrocyte lactate-pyruvate ratios have been reported to be useful as an indication of schizophrenic illness.5,6 However, attempts to repeat these studies have but limited success.7,8 In addition, there is a possibility that there may be present in some human subjects an antibody against chicken erythrocytes which could cause a partial lysis of these cells with a concomitant rise in glycolysis. This may account for reported alterations in chicken erythrocyte metabolism produced by the plasma of certain schizophrenic patients.9 In this type of study, therefore, complications could arise due to interspecific protein-protein reactions, eg, antibody-antigen reactions.
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